Table 6 Methodologic rigor

Etiology

Observations concerned with the relationship between exposures and putative clinical outcomes;

Data collection is prospective;

Clearly identified comparison group(s);

Blinding of observers of outcome to exposure.

Prognosis

Inception cohort of individuals all initially free of the outcome of interest;

Follow-up of ≥ 80% of patients until the occurrence of a major study end point or to the end of the study;

Analysis consistent with study design.

Diagnosis

Inclusion of a spectrum of participants;

Objective diagnostic ("gold") standard OR current clinical standard for diagnosis;

Participants received both the new test and some form of the diagnostic standard;

Interpretation of diagnostic standard without knowledge of test result and vice versa;

Analysis consistent with study design.

Treatment

Random allocation of participants to comparison groups;

Outcome assessment of at least 80% of those entering the investigation accounted for in 1 major analysis at any given follow up assessment;

Analysis consistent with study design.

Economics

Question is a comparison of alternatives;

Alternative services or activities compared on outcomes produced (effectiveness) and resources consumed (costs);

Evidence of effectiveness must be from a study of real patients that meets the above-noted criteria for diagnosis, treatment, quality improvement, or a systematic review article;

Effectiveness and cost estimates based on individual patient data (micro-economics);

Results presented in terms of the incremental or additional costs and outcomes of one intervention over another;

Sensitivity analysis if there is uncertainty.

Clinical Prediction Guide

Guide is generated in one or more sets of real patients (training set);

Guide is validated in another set of real patients (test set).

Review articles

Statement of the clinical topic;

Explicit statement of the inclusion and exclusion criteria;

Description of the methods;

≥ 1 article must meet the above noted criteria.